Nuclear Magnetic Resonance (NMR) spectroscopy and imaging are powerful tools for obtaining detailed molecular structure and dynamics information for samples under investigation. NMR methods address numerous chemical, physical, and biological problems across various scientific disciplines. Magic Angle Spinning (MAS) is one of the most widespread NMR methods and is the only technique that allows a high resolution NMR spectrum to be acquired on solids, semi-solids, and mixtures of various sample materials. In MAS NMR, a sample is spun at a sample spinning rate of several kHz or more about an axis inclined at an angle of 54.74 degrees (°) with respect to the main magnetic field. Sample spinning speeds are used to average out line-broadening effects arising from common shielding interactions including, e.g., chemical shift anisotropic-gradients, dipolar-gradients, and magnetic-susceptibility gradients to give high-resolution NMR spectra. However, despite its wide spread application, MAS has not yet been reported in the literature at high-pressure conditions exceeding 70 bar due to various technical challenges that remain to be addressed. First, sample carriers cannot be made of metals due to strong eddy currents associated with a spinning metal in a strong magnetic field. This leaves non-metals for sample carriers including glasses, ceramics, and polymer plastics. Early development efforts in high-pressure MAS NMR investigated segmental motion of polymers (i.e., interchain distances within polymers) that were plasticized by dense gases. The sample carrier was a glass tube insert in which gas was cryogenically transferred into the carrier using a standard volumetric absorption method. The carrier was then flame-sealed or epoxy-sealed and subsequently inserted into a MAS rotor and balanced with KBr powder. The carrier was pressurized with xenon (Xe) and CO2 gases. However, (i) reactions under a constant pressure were not obtained, (ii) maximum upper pressure was limited due to the use of thin glass tubes, and (iii) the carrier could not be re-opened to recharge and continue the sample reactions. A later carrier insert was made of DELRIN™ polymer that included an internal seal. The DELRIN™ insert included a cylindrical design that was inserted into a ceramic MAS rotor after pressurization. A 94.2 MHz 19F MAS spectrum of CH3F gas was acquired using this carrier insert. However, significant penetration by the CH3F molecules into the DELRIN™ polymer material was observed over time, with a corresponding reduction in pressure. Similar penetration problems have been reported in the literature with CO2 and N2O gases using MAS inserts made from the polymer PEEK®. In these experiments, pressure was limited because a fast sample spinning of several kHz or more was required. The sample rotor required a small diameter, which complicated the sealing necessary to attain high-pressures with this design. Polymer inserts made of polymers such as DELRIN™ and PEEK® are commonly plagued by strong unwanted carbon and/or proton background signals which can mask desired NMR signals in systems containing carbon, protons, or both. Thus, a high-pressure rotor is needed that provides sealing at high reaction temperatures and pressures, minimizes penetrations by sample molecules and fluids at high reaction temperatures and pressures, and minimizes background signals that complicate the desired signal, permitting high-resolution NMR spectra and images to be generated. The present invention meets these needs by addressing various problems known in the art. Additional advantages and novel features of the present invention will be set forth as follows and will be readily apparent from the descriptions and demonstrations set forth herein. Accordingly, the following descriptions of the present invention should be seen as illustrative of the invention and not as limiting in any way.